This is an excerpt from my 2021 book, Sensible Decarbonization: Regulation, Risk, and Relative Benefits in Different Approaches to Energy Use, Climate Policy, and Environmental Impact
Our lives frequently involve consideration of supply and
demand issues. Usually, what is being supplied or needed is energy, or some
proxy for energy. Electricity, heat, and mobility are energy. Wealth is often a
proxy for energy too. Energy is a big part of the cost of most anything. We
need to consider how much gas is in the car, how much propane, fuel oil,
firewood, pelletized wood, or other fuel is in store. We need to monitor our
electricity use to prevent surprisingly high bills. We need to charge and
recharge our batteries. With natural gas and electricity, it is more pay as you
go but we need to consider seasonal cost fluctuations. With solar it is hope
for sunnier days, but averages are quite predictable. With rooftop solar one is
buying in bulk, several years ahead, but getting a decade or three of free
energy after that, if the inverter holds out. Energy is food for our machines
says Alex Epstein.[1]
The most common definition of energy is “the capacity to do work.”
However, Vaclav Smil reminds us that it is not quite so simple. He writes that
“Energy is not a single, easily definable entity, but rather an abstract
collective concept, adopted by nineteenth-century physicists to cover a variety
of natural and anthropogenic (generated by humans) phenomena. Its most commonly
encountered forms are heat (thermal energy), motion (kinetic or mechanical
energy), light (electromagnetic energy), and the chemical energy of fuels and
foodstuffs.”[2]
Robert Bryce in A
Question of Power: Electricity and the Wealth of Nations, notes that
electricity requires three prerequisites: integrity, capital, and
fuel. Integrity refers to having a functional “system” where corruption
does not impede the building and supplying of electricity.[3]
Since energy in some form is often a major component of things with monetary
value, we tend to conserve it and make it efficient as we are able. At the same
time, energy lets us meet our comfort, industrial input, and mobility goals.
Increases in energy costs lead directly to increases in the costs of products
and services, which is the ‘double whammy’ of expensive energy. The likelihood
is that a highly accelerated decarbonization will increase energy costs, and
thus products and services costs, for everyone. Low energy costs boost the
economy. High energy costs do the opposite. Relative costs of efficiency, wind,
solar, and storage improve in a high energy cost environment. Solar and for the
most part wind, are immune from fuel price fluctuations and their installation
and deployment prices have been coming down, albeit slow, for a long time and
that is likely to continue. However, if the supply of the minerals and
materials used in the manufacture of solar, wind, batteries, and EVs becomes
constrained due to more widespread accelerated decarbonization then prices
could rise so minerals and materials price fluctuations are a consideration.
Fuels like oil and natural gas are cheap for consumers and profitable for
producers due to technology improvements. They are cheap enough, in the case of
road fuels like gasoline and diesel, to be taxed significantly at federal,
state, and local levels and still be affordable. EVs do have a significant
“fuel” cost advantage over internal combustion vehicles due to the superior
energy efficiency of electric engines – if we consider the electricity to be
the fuel. In some places like parts of smog-prone California, air pollution is
a major consideration, especially for diesel and gasoline trucks, which are big
contributors. Natural gas vehicles, EVs, and CAFÉ standards have been deployed
to mitigate those affects.
Energy
Density Means That Wind Turbines and Solar Panels Will Fill the Country-sides
of Earth in a 100% Renewables Scenario
Vaclav Smil and
Robert Bryce have repeatedly reminded us about energy density and what
that would mean for a world run on wind and solar. More specifically it is power
density (in watts per square meter) that is problematic. Compared to fossil
fuels wind and solar are not energy dense nor power dense and so require vastly
more space. Will we deforest areas to put up wind turbines and solar panels or
just put up wires to bring them from distant treeless areas? Likely both. Average
wind turbine efficiency has risen due to higher towers and bigger turbines to
35% or more. The Betz Limit, or Betz Law for wind turbines is about 59.3%
efficiency which is the maximum theoretical limit of energy extractable from
wind, and although there are some who think it could be overcome, most do not.
This means that they can’t get much more efficient due to the limitations of
wind and wind capture. Some bigger turbines are currently above 45% so the room
for further improvement is getting smaller.[4]
The theoretical limit for typical one-junction solar cell efficiency is just
under 34% and some panels can currently reach 25% for higher cost versions so
like wind that limit is approaching. The average solar panel efficiency is currently
around 20.5%. That means the cost improvements will likely slow their growth
fairly soon as efficiency approaches theoretical limits.[5]
Net-zero by 2050 scenarios show that quite vast amounts of land must be covered
by solar panels and wind turbines in order to succeed and things like expedited
permit approvals and eminent domain will be required to get transmission lines built.
[1] Epstein, Alex 2014. The Moral Case for Fossil Fuels,
Portfolio/Penguin, 2014.
[2] Smil, Vaclav, 2017. Energy: A Beginner's Guide
(Beginner's Guides), Oneworld Publications; 2nd Edition.
[3] Bryce, Robert, 2020. A Question of Power: Electricity
and the Wealth of Nations. PublicAffairs.
[4] Windpower Engineering, Oct. 23, 2009. Can we Overcome
the Betz Limit in Windpower Extraction? www.Windpowerengineering.com
[5] Wikipedia entry – ‘Solar cell efficiency,’ Retrieved
Sept. 17, 2020.
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